In recent years, digital signage has drawn attention that allows a variety of advertising contents to be delivered at low cost. In many cases, a transmissive display such as a liquid crystal display (LCD) is typically used for the digital signage. However, when such a display is used outdoors, it has difficulty in achieving a contrast ratio, and lacks visibility. Further, such a display has to carry out light emission not to be affected by outside light such as sunlight, thus leading to higher power consumption.
Meanwhile, as a display that achieves low power consumption, a reflective display such as an electronic paper that uses an electrophoretic display device has attracted attention. The electronic paper has come to be used also for display applications with low rewrite frequency such as a digital clock as well as for the digital signage application. The electronic paper is used in such a manner that power is once turned off upon completion of rewriting of one image, and thereafter power is turned on again at the time of new rewriting operation. This causes the contrast to be varied depending on elapsed time (update time) after power-off, resulting in deterioration in the visibility. Such a display property is referred to as memory performance. Further, a luminance difference is generated between a portion for which new rewriting operation is performed and a portion for which no rewrite operation is performed, leading to occurrence of a phenomenon referred to as a residual image. Such a phenomenon may provide a feeling of discomfort to a user.
Thus, PTL 1 proposes a method of applying supplementary pulses in the middle of write operation. The use of the supplementary pulses allows for compensation for a decrease in reflectance over time, which makes it possible to suppress the luminance difference between a rewritten portion and a non-rewritten portion, leading to suppression of occurrence of the residual image.